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在修建阿斯旺高坝之前,每年的尼罗河洪水给埃及地中海沿岸水域输送了约7～11×10~3t生物有效磷(P),至少7×10~3t无机氮(N)以及110×10~3t硅(Si)。这些营养物质刺激了维系富饶渔业的尼罗河硅藻的迅速大量繁殖。自1965年高坝合龙之后,尼罗河的水流量减少了90%以上、渔业也因此而崩溃。20世纪80年代期间,渔业开始迅速恢复,这得益于化肥使用的增加、农业排水面积的扩大、人口增长以及城市供水和污水处理系统的迅速发展。营养物质(磷和氮,但不包括硅)的潜在人为贡献量的计算结果符合关于人类污水和农业排水目前维系着以前曾由尼罗河提供的肥力的假设,尽管目前维系着渔业的生产性生态系的性质看起来与历史上的显著不同。
Prior to the construction of the Aswan High Dam, annual Nile floods deliver about 7-11x10-3 t of P, at least 7x10-3 t of inorganic nitrogen (N) and 110x10 ~ 3t silicon (Si). These nutrients stimulate the rapid mass propagation of the diatoms that sustain the richness of the Nile. Since the closure of the high dam in 1965, the Nile’s water flow has been reduced by more than 90% and the fishing industry has also collapsed. Fisheries began to recover rapidly during the 1980s thanks to increased use of fertilizers, an expansion of agricultural drainage, population growth and the rapid development of urban water and sewerage systems. The calculation of the potential anthropogenic contribution of nutrients (phosphorus and nitrogen, but excluding silicon) complies with the assumption that human sewers and agricultural drains currently sustain the fertility previously provided by the Nile, although the productive ecosystems of fisheries are currently maintained The nature of it looks remarkably different from that of history.